1. Field of the Invention
The present invention relates to remediation of bodies of water, and, more particularly, to wetland technologies for such remediation, and, most particularly, to the use of wetland plants in large subsidiary bodies of water for such remediation.
2. Description of Related Art
In order to remove nutrients from a body of water, it is known in the art to use macrophytes, that is, wetland plants, the root zones of which remove these nutrients from the water body. The macrophyte vegetation takes up the soluble nutrients as a function of their growth.
Many types of floating vegetation, particularly large-leaved species such as water hyacinth (Eichhomia crassipes), pennywort (Hydrocotyle sp.), and water lettuce (Pistia stratiotes), have been utilized for enhancing the quality of surface waters and wastewaters. The plants improve water quality in part by virtue of their rapid vegetative growth rates and high nutrient assimilative capacity.
Such floating plants spread primarily by vegetative means, and can rapidly cover the surface of a water body due to their rapid replication (specific growth) rates. In natural water bodies, such floating plants usually are considered noxious aquatic weeds.
In relatively large bodies of water, however, complete coverage of floating plants typically does not occur quickly because of their tendency to be transported by winds and currents, which can effectively compress plants onto one side of a water body. When compacted in such a fashion, many floating plants (e.g., water hyacinths) tend to increase their biomass by growing taller, rather than spreading horizontally by producing additional small (daughter) plants. Once plants are tall and compacted, this often compromises their ability to colonize the entire water body.
Other factors that can slow or totally arrest the proliferation of floating plants are the presence of disease organisms or arthropod pests, or an inadequate complement of nutrients in the water body.
In water and wastewater treatment applications, where it is desirable to achieve total coverage of floating plants as rapidly as possible, one solution has been to cover large bodies of water with floating containment grids that are anchored in place. This effectively creates smaller chambers for the plants to fill.
However, with extremely large bodies of water, it is impractical to cover the water surface with a sufficiently fine grid that the compression effect does not still limit plant growth.
Therefore, it would be desirable to provide a system and method for facilitating the rapid proliferation of floating aquatic plants, particularly on large bodies of water.